It will take an Expert to diagnose this one.

I have a 2000 Olds Alero 3.4L
About 2 months ago a roaring noise started somwhere in the front end.
It sounds like an airplane - or when you drive over "rumble strips"
Here is what I know. I replaced both Wheel Bearings (Driver and Passenger).
I replaced the Driver side drive axle (I suspected a bad CV joint) - didn't fix it.
The noise has changed to a "clunking or knocking" somewhere on hte passenger side.
It only changes with speed. Noise is the same no matter what gear I am in - even Neutral.
Turing the wheel makes the noise worse and better. (that is why I first changed the wheel bearings).

So I assume it has to bee somewhere in the drive line. The only parts I have not changed yet are the passenger side drive axel (no sign of leaking CV boot) and I have not done anything with the transaxle.

I am ok with replacing the driveaxle but wnat to make sure it is not something in the transaxle first. How do I figure this out? When the clunking / knocking / roaring happens - you can feel it in the pedals and on your feet. Almost like someone is tapping the underside of the car with a hammer.

Is this a CV joint problem? or I have read a little about a transaxle bearing problem (what is that)?

Tough to tell from here without an onsite road test, check for loose caliper bracket bolts.

Was the noise EXACTLY the same after replacing the wheel bearings?

Have you checked your tires for abnormal wear or cupping?

If you know the noise is in the front, try a tire rotation to see if the noise moves to the rear.....

I'm with TechII, Check and rotate the tires. Like Maxwedge said, hard to tell without a test drive.

I rotated the tires and this did not make any difference. The noise is coming either from the drive axle or inside the transaxle. *Improtant note: When I changed the passenger side wheel bearing the noise changed from a roaring humm - to a clunking and knocking sounds. My only guess is that when pushing the drive axle out of the hub, a problem in the CV joint got worse.

I am having the same problem with my 2004 Alero and I can't figure out where the airplane humm is coming from. Rotated tires etc... particularly bad from about 35 mph to about 55 mph...